The present invention relates to a method for rectifying color blindness and eyeglasses employed therein.
As a genetic disease, color blindness is believed incurable. At present there are at least 2.5 hundred million people suffering from abnormal color vision. Before the present invention, whether color blindness was rectifiable had been under discussion, and research had been conducted in this field, resulting in no breakthrough achievements. As early as in 1878, Delboeuf and Spring noted that red optical filtering devices may be used to help abnormal color viewers to discriminate between different color objects. Many types of optical filtering devices were designed to improve the color blind viewers' ability to distinguish pseudo-isocolors. For example, U.S. Pat. No. 4,300,819 discloses a pair of improved eyeglasses which can aid color discrimination for color blind viewers. The eyeglasses have two lenses, one is clear and the other is colored. To appear identical to the observers, each lens is additionally coated or formed to have a reflective or mirror-like surface. This kind of eyeglasses can only improve color sensation of the color blind viewers. U.S. Pat. No. 5,149,183 also discloses color enhancing sun glasses which attenuate blue and red light thereby preventing human eyes from harmful effects of such light. The transmission curves therein are specifically designed to attenuate certain light not to correct color blindness.
At present, all researchers only use various optical filtering devices, experimentally to rectify color blindness. There are no devices to test color blindness quantitatively. In fact, the light sensitivity of eyes in the range of visible light differ with wavelength. It is believed in physiology that color blindness is caused by some errors occurring during recognition of colored objects. The errors may occur during certain physiological processes of transmission of color signals in retina. The external manifestation of color blindness is the change of sensitivity of eyes in the range of visible light. Whereas optical filtering devices in the patents above could rectify color blindness in certain degrees, there is not theoretical basis therefor and the effects are poor. The reason is that prior art optical filtering devices are not designed according to the spectral sensitive curves of the abnormal color viewers. Moreover it is impossible to rectify all kinds of color blindness simply using single or compound optical filtering devices. One should adopt different optical filtering devices for different spectral sensitive curves of abnormal color viewers.